1. Field of the Invention
The present invention relates to a cable connector. More particularly, the present invention relates to a multipin cable connector.
2. Description of the Related Technology
EP 0 684 666 B1 discloses a multipin cable connector. This cable connector has a cable receiving part into which individual flexible leads are inserted for making axial contact of their plug-side end sections with the cable-side end areas which are configured as contact spikes. Upon insertion, the contact spikes penetrate axially into the individual leads such that contact is made.
In studying a cable connector over an extended period, it has been found that the force in the contact area of the contact spike decreases with time so that after prolonged use of the cable connector; reliable contact-making is no longer ensured. Data transmission or power supply via such a cable connector is not always guaranteed. As will be appreciated by one of ordinary skill in the art, when data transmission or power supply fails, undesirable effects, especially in situations critical to safety, can occur.
Therefore one object of the invention is to devise a cable connector of the aforementioned type for connection of single-core or multicore stranded cable of any configuration, in which permanently reliable contact-making is ensured.
This and other objects may be achieved by providing a cable connector having a cable receiving part for holding a cable end, wherein said cable end is mechanically pretensioned in said cable receiving part after connection by a contact-making means.
According to one aspect of the invention, the contact-making means comprises an insulation piercing connecting device which secures the cable end in the cable receiving part such that after connection it is mechanically pretensioned. Using an insulation piercing connecting device ensures that the cable end can be inserted into the cable receiving part quickly and easily, i.e. without major prior effort, which prevents stripping the insulation.
The insulation piercing connecting device during installation ensures that the outer insulation of the cable end may be split and electrical contact with the core of the cable is established. Because the insulation piercing connecting device fixes the cable end in the cable receiving part such that after electrical connection it is under stable mechanical pretension, permanently reliable contact-making is ensured since as a result of this pretensioning the cable end is always pressed in the direction of the insulation piercing connecting device or vice versa. As will be appreciated by one of ordinary skill in the art, this is of great importance when the core of the cable consists of copper leads since copper has the property of creeping.
The cable connector is preferably used for single-core cable, but of course may also be used for several individual cables and also for a single multipin cable. The structural shape of the cable connector (round, square or the like) is irrelevant.
According to one aspect of the invention, the cable receiving part has a line chamber which is larger in cross section than the cross section of the cable. The cable end is thus guided along the line chamber when inserted into the cable receiving part. At the same time, the cable end after fixing in the cable receiving part can move slightly when contact is made with the insulation piercing connecting device, resulting in mechanical pretensioning. In the penetration or contact-making area, especially in the X-Y plane, it is not necessary to route the cable end along a defined path. As will be appreciated by one of ordinary skill in the art, this provides for a simple configuration of the cable receiving part and its assembly. As will also be appreciated, another advantage lies in the use of cable ends with differing thicknesses.
According to another aspect of the invention, the cable receiving part has a clamping sleeve. This clamping sleeve can be inserted either after insertion of the cable end into the cable receiving part or inserted when the cable end is being inserted into the line chamber and can be penetrated by the cable end. After the cable end has been inserted into the line chamber, the clamping sleeve is attached (preferably mechanically) and fixes the position of the cable end with reference to the cable receiving part. Alternatively, before the cable end has been inserted, the clamping wedges can be made as barbs, which after insertion of the cable end, hold the latter. In this installation step, provisions can be made for the piece of the cable end which is located in the line chamber to be under mechanical pretension. This increases the effectiveness of contact-making since this mechanical pretensioning arises when contact is made with the insulation piercing connecting device. In addition, fixing the cable end by means of the clamping sleeve results in the cable end being unable to move out of the line chamber when contact is made with the insulation piercing connecting device. Instead of a clamping sleeve it is of course also conceivable for the cable to be fixed detachably or permanently in the line chamber, with the last piece of the cable remaining freely movable in the line chamber. With respect to permanent fixing, it is also possible to cement the cable in the top end of the line chamber. The use of a clamping sleeve, however, has the advantage that it can be both inserted mechanically and also fixed.
According to another aspect of the invention, the insulation piercing connecting device is located in a receiving means for insulation piercing connecting devices. The receiving means for the insulation piercing connecting devices can be connected to the cable receiving part. Thus, as described above, the cable end can be inserted into the cable receiving part and fixed. The insulation piercing connecting device may then penetrate into the lower area of the line chamber by feed of the receiving means for the insulation piercing connecting devices and cause contact to be made. Finally, the cable receiving part and the receiving means for the insulation piercing connecting devices may be connected to one another (for example, by clipping, screwing, welding, cementing or the like) to form a finished cable connector. The insulation piercing connecting device on its side facing away from the contact area has connection means, such as contact pins, contact tubes or the like. They can be exposed or can also be concentrically surrounded by part of the receiving means for the insulation piercing connecting devices.
According to another aspect of the invention, the line chamber tapers in its end area (contact area). This tapering results in a transverse arrangement of the cable end buckling direction, by which further alignment of the cable end to the spring direction of the insulation piercing connecting device is no longer necessary. Furthermore, due to this tapering (wedge-shaped configuration) of the line chamber it can be provided with cable ends (wires) of different diameters. For different diameters the tapering causes the cable end to be guided in the direction in which the cable end assumes a position in which it can be reliably penetrated by the insulation piercing connecting device.
According to another aspect of the invention, the line chamber has a diamond-shaped cross section. This configuration of the cross section of the line section ensures that the cable end has enough room for slightly curved deformation, and that centering takes place which ensures that upon making contact with the insulation piercing connecting device the cable end cannot recede such that contact is not made.
According to yet another aspect of the invention, the center lines of the insulation piercing connecting device and the line chamber are flush, parallel or tilted to one another. The almost axial or ideally axial penetration of the insulation of the cable end yields a large-area, highly redundant, permanently elastic and gas-tight electrical connection between the insulation piercing connecting device and the conductive core of the cable end.